Mammography facilities frequently use inreach strategies, such as reminders, to encourage annual returns by asymptomatic women 50 years of age and older. We describe three pilot studies that systematically compared various strategies. In each study, patients seen for a screening mammogram during a specified period were randomly assigned to a novel reminder condition or a comparison condition one year later, and return rates were monitored. In study 1, return rates for subjects receiving a standard mailed reminder (36%) and subjects receiving a mailed reminder plus incentive (32%) were similar. In study 2, return rates for subjects receiving a mailed reminder (44%) and subjects receiving a phoned reminder (48%) also were similar. However, study 3 focused on a mailed reminder on the referring physician's letterhead sent by the mammography facility versus no reminder, and a significant increase in return rates resulted (47% versus 19%). We present the implications of this pattern of findings and discuss the need for a larger trial of the physician-endorsed reminder.